A current trend in lighting is that light is more and more used for creating an atmosphere rather than for simple illumination. Lighting solutions suitable as “atmosphere providers” need to be capable of emitting light of different colors as well as being variable in intensity (dimmable). Ideally, such lighting solutions should be variable over the entire color triangle (for example in the xy-plane of the CIE XYZ-system) perceptible by a human eye. In reality, however, a color variable lighting solution can span only a part of the color triangle. For a particular color variable lighting solution, this part of the color triangle is referred to as the color gamut of the lighting solution. Moreover, different lighting solutions generally have different color gamuts.
U.S. Pat. No. 5,384,519 discloses an example of such a variable color lighting arrangement in which light from at least three dimmable mono-color light sources is mixed in order to emit light of a desired color.
Since the color gamut of any variable color lighting solution only spans a part of the color triangle, there is always a possibility that a user may request light of a color outside the color gamut of the lighting solution. Furthermore, the variable color lighting system may, at a given time, be unable to emit light of a color, which is within the specified color gamut. This may happen due to variations over time, temperature etc in the light-sources comprised in the lighting system.
There is thus a need for an improved variable color lighting system which is capable of handling requested out-of-gamut color points in a satisfactory way.